Thanks to everyone who responded.
I did have FU grafts, although the number of grafts was substantially less than represented, and a high level of density was not acheived. I wonder whether when there is insufficient density, there is also a decreased level of electrostatic attraction between the hairs, and therefore an increased tendancy of the individual hairs to go their own way, resulting in the frayed look?
The theory about damage to the sebaceous glands is also interesting. The technician dissecting the grafts seemed rushed to keep up, and maybe was not able to obtain as much precision as possible. My hair is naturally oily, so perhpas decreased production arounded the transplanted hairs partly explains the difference in texture?